Atomic Structure, Ions, & Isotopes

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Transcript of Atomic Structure, Ions, & Isotopes

Isotopes & IonsWhat is an atom?Atom: The smallest part of an element that still has the element's properties Structure:Nucleus:-Center of the atom-Nearly all of the mass-Contains protons and neutrons

Electron Cloud:-Surrounds the nucleus-Contains electrons

Size of an Atom-Atoms are EXTREMELY small.-Think apple to the earth

-The nucleus is even smaller. -Think marble in the middle of MetLife Stadium So, what is the rest of the atom?EMPTY SPACE!Subatomic ParticlesThe smaller parts of an atom++--++-Electrons:-Located in the electron cloud-Negative Charge -Relative size of 1/2000 (negligible mass)e-Protons:-Located in the nucleus-Positive Charge -Relative size of 1p+Neutrons:-Located in the nucleus-Neutral Charge (no charge) -Relative size of 1noProtons and Neutrons make up the mass of the atomProtons and electrons balance, giving the atom a net charge of zero in its normal statep+e-Atomic # and Mass #XAZElement symbol (X)Atomic Number (Z)The number of protons in the atomAtomic # NEVER changes Unique for every elementEvery atom of the same element has that atomic numberThe periodic table is arranged by increasing atomic numberMass Number (A)The total number of protons and neutrons (the mass)Mass # can vary Allows us to calculate the number of neutronsMass # - Atomic # = # of Neutrons Examples:Element Atomic # Mass # p+ e- n 1 1 1 1 0HLiAlCrCaKr

*Mass on P.T.% abundance in decimals!MassEx. Average Atomic Mass of Siliconhttp://www.sisweb.com/referenc/source/exactmas.htmMass Spectrometer Chemists use a mass spectrometer to separate and identify different isotopes of an element The isotopes are separated based on their massA resulting graph shows the relative or percent abundance of each isotope Using this data, calculate the average atomic mass of Magnesium: (24 x 0.79) + (25 x 0.10) + (26 x 0.11) =24.32 amu IonsIons: Charged Particles - atom or group of atoms with a positive or negative charge (Same # of protons, different # of electrons)CationAnionPositive ChargeAtom has lost 1 or more electrons Tend to be metals (left side of P.T.)Negative ChargeAtom has gained 1 or more electrons Tend to be non-metals (right side of P.T.)11 electrons10 electronsProtons and electrons are no longer balancedCharge is shown as a superscript10 electrons9 electronsIsotopic Notation:Warm Up1. What charge do protons, neutrons, and electrons have?

2. Which particle determines the identity of an atom (which element it is)?

3. Which particle is involved in reactivity (allows atoms to react with one another)?

4. What is the very center of an atom called?PracticeElement # of Protons # of Electrons Charge Na 10 Ca +2 Cl 18 P -3 S 181. How many protons, neutrons, and electrons are in the following atoms:

2. What is the average atomic mass of an element with 3 isotopes - one with a mass of 29.5 and % abundance of 24.5, one with a mass of 31.7 and % abundance of 70.5 and one with a mass of 30.2 and % abundance of 5.0?Br80

35Mg24

122+

N14

73-

Warm UpHow many protons, neutrons, and electrons are in the following?